1. Field of the Invention
The present invention relates to a method of fabricating a diaphragm of a capacitive microphone device, and more particularly, to a method of fabricating a diaphragm of a capacitive microphone device that has silicon spacers.
2. Description of the Prior Art
Capacitive microphone device has a parallel capacitor composed of a diaphragm and back plate. When the diaphragm senses a sound pressure and vibrates, the capacitance between the diaphragm and the back plate will change. Generally speaking, the capacitive microphone device can be classified into two types: electret type and condenser type. For a capacitive microphone device, the diaphragm is used to sense the sound pressure, and therefore requires good uniformity to accurately reflect the volume and frequency of sound.
The diaphragm of a conventional capacitive microphone device is made of plastic, and formed by stamping. The plastic diaphragm is mounted on the back plate by spacers. However, the plastic diaphragm formed by stamping has poor yield and uniformity. In addition, the conventional method, which assembles the diaphragm with spacers after the capacitive microphone device, requires high cost and much cycle time.